Yeah, probably debconf should be used to ask which webservers should be configured (or not). However, this doesn't strike me as being that important since Drupal has a quite good multisite behavior, i.e. it won't show anything under a domain for which it hasn't been configured.
-- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org